Weather Briefing for The 2013 Presidential Inauguration NOAA / National Weather Service Baltimore/Washington Weather Forecast Office January 21, UTC / 2:00 PM EST Steven Zubrick Science and Operations Officer

Outline Weather HazardsWeather Hazards Current Observations/RadarCurrent Observations/Radar Forecast OverviewForecast Overview Forecast Tables and GraphsForecast Tables and Graphs Reagan and Dulles METAR & TAFReagan and Dulles METAR & TAF Illumination DataIllumination Data Space WeatherSpace Weather Dispersion ModelingDispersion Modeling Summary of Weather HazardsSummary of Weather Hazards Briefing ScheduleBriefing Schedule 1/21/ PM EST2NWS Baltimore/Washington Weather Forecast Office

Weather Hazards 1600 UTC 21 Jan – 1200 UTC 22 Jan 2013 for Washington, D.C. 30% chance of a snow squall (Sometime between 5:00 PM and 09:00 PM today) Arctic cold front may produce a snow squall that could produce up to 1 inch of snow.Arctic cold front may produce a snow squall that could produce up to 1 inch of snow. Gusty Winds (30 mph tonight, 35 mph Tuesday) Gusty Winds (30 mph tonight, 35 mph Tuesday) Small Craft Advisory for the Potomac starts at Noon today.Small Craft Advisory for the Potomac starts at Noon today. Wind chills will drop below 20 after midnight, and will fall to the upper single digits by dawn Tuesday.Wind chills will drop below 20 after midnight, and will fall to the upper single digits by dawn Tuesday. 3NWS Baltimore/Washington Weather Forecast Office 1/21/ PM EST

NWS Baltimore/Washington Weather Forecast Office 4 Regional Radar/Surface Mosaic 1800 UTC 21 Jan 2013

1/21/ PM ESTNWS Baltimore/Washington Weather Forecast Office 5 Regional Visible Satellite 1745 UTC 21 Jan 2013

Forecast Overview for Washington, D.C. 6NWS Baltimore/Washington Weather Forecast Office Normals: High: 43F Low: 28F 1/21/ PM EST

1/21/ AM ESTNWS Baltimore/Washington Weather Forecast Office 7

Weather Element Forecast for Washington, D.C. 8NWS Baltimore/Washington Weather Forecast Office 1/21/ PM EST

KDCA METAR & TAF Ronald Reagan National Airport METAR METAR KDCA Z 18006KT 10SM BKN100 06/M07 A2996 RMK AO2 SLP146 T TAF KDCA Z 2118/ KT P6SM OVC080 FM KT P6SM OVC070 FM KT P6SM OVC060 FM G27KT P6SM SCT200 9NWS Baltimore/Washington Weather Forecast Office 1/21/ PM EST

KIAD METAR & TAF Dulles International Airport METAR METAR KIAD Z 16008KT 10SM OVC090 04/M06 A2993 RMK AO2 SLP138 T TAF KIAD Z 2118/ KT P6SM OVC080 FM KT P6SM OVC060 FM G23KT P6SM BKN050 FM G27KT P6SM SCT150 FM KT P6SM FEW250 10NWS Baltimore/Washington Weather Forecast Office 1/21/ PM EST

DateSRSSMRMSLunar Illumination (%) 19-Jan Z/0723L2215Z/1715L1639Z/1139L20/0653Z-20/0153L60% 20-Jan Z/0723L2216Z/1716L1716Z/1216L21/0748Z-21/0248L69% 21-Jan Z/0722L2217Z/1717L1756Z/1256L22/0841Z-22/0341L77% 22-Jan Z/0722L2218Z/1718L1840Z/1340L23/0930Z-23/0430L84% 23-Jan Z/0721L2219Z/1719L1929Z/1429L24/1016Z-24/0516L91% 24-Jan Z/0720L2221Z/1721L2021Z/1521L25/1058Z-25/0558L95% 25-Jan Z/0720L2222Z/1722L2117Z/1617L26/1136Z-26/0636L98% Illumination Data Washington, D.C. 11NWS Baltimore/Washington Weather Forecast Office 1/21/ PM EST

Space Weather Summary/Forecast Space Weather Activity SummaryForecast Past 48 Hours Current Next 24 Hours Solar Flare Radio Blackouts (R Scale) None R1 – Slight Chance Solar Radiation Storms (S Scale) None Geomagnetic Storms (G Scale) None Joint NOAA/USAF Space Weather Briefing Jan. 21, UTC Summary/Forecast Details: Region 1654 continues to decay and will begin to rotate off the disk on 21 January. Currently quiet across S and G scales Overall threat of significant space weather activity is low Geomagnetic Storms Solar Flare Radio Blackouts

Phenomena Reference/Impacts Joint NOAA/USAF Space Weather Briefing Jan. 21, UTC Solar Flare Radio Blackout (R Scale): No advance warning Effects lasts for 10’s of minutes to several hours Impacts High Frequency (HF) communication on the sunlit side of the Earth First indication significant S and G scale activity may be possible Solar Radiation Storm (S Scale): Warnings possible on the minutes to hours time scale Elevated levels can persist for several days Impacts to the health and operation of satellites and International Space Station operations and crew Impacts High Frequency communication in the polar regions, affecting commercial airline operations Geomagnetic Storm (G Scale): Advance notice possible given coronal mass ejection (CME) transit times from Sun to Earth range from just under a day to several days (CMEs being the main driver of significant storms) In extreme storms, impacts to power grid operations and stability Impacts to Global Positioning System (GPS) accuracy and availability Driver of aurora; severe to extreme storms may cause aurora to be visible over most of the lower 48 Complete NOAA Space Weather Scale information available online at:

14NWS Baltimore/Washington Weather Forecast Office HYSPLIT DISPERSION MODEL 12Z NAM 1/21/13 Release at 1700Z 21 Jan 2013 (NAM) Release at 2300Z 21 Jan 2013 (NAM) 1/21/ PM EST

Always up to date NOAA/NWS Baltimore/Washington 15NWS Baltimore/Washington Weather Forecast Office 1/21/ PM EST

Summary Inauguration Day:Inauguration Day: Mostly cloudy and mild, but cooler than yesterdayMostly cloudy and mild, but cooler than yesterday Turning cold in the eveningTurning cold in the evening 30% chance of a snow squall after 5 P.M.30% chance of a snow squall after 5 P.M. This could produce a quick accumulation of snow from a dusting to one-half inch.This could produce a quick accumulation of snow from a dusting to one-half inch. Monday Night:Monday Night: 30% chance of a snow squall remains until 10 P.M.30% chance of a snow squall remains until 10 P.M. Then clearing and coldThen clearing and cold Gusty northwest winds to 30 mphGusty northwest winds to 30 mph Lows by dawn in the lower 20sLows by dawn in the lower 20s Wind chills by dawn in the upper single numbersWind chills by dawn in the upper single numbers 16NWS Baltimore/Washington Weather Forecast Office 1/21/ PM EST

Briefing Schedule T-7 days: Tue Jan ESTT-7 days: Tue Jan EST T-6 days: Wed Jan ESTT-6 days: Wed Jan EST T-4 days: Thu Jan ESTT-4 days: Thu Jan EST T-3 days: Fri Jan ESTT-3 days: Fri Jan EST T-2 days: Sat Jan ESTT-2 days: Sat Jan EST T-1.5 Day: Sat Jan ESTT-1.5 Day: Sat Jan EST T-1 Day: Sun Jan ESTT-1 Day: Sun Jan EST T-14 hours: Sun Jan ESTT-14 hours: Sun Jan EST T-12 hours: Mon Jan ESTT-12 hours: Mon Jan EST T-9 hours: Mon Jan EST (if needed)T-9 hours: Mon Jan EST (if needed) T-6 hours: Mon Jan ESTT-6 hours: Mon Jan EST T-3 hours: Mon Jan ESTT-3 hours: Mon Jan EST T-1 hour: Mon Jan EST T+2 hour: Mon Jan ESTT+2 hour: Mon Jan EST T+5 hour: Mon Jan ESTT+5 hour: Mon Jan EST Other times / dates as needed or requested 17NWS Baltimore/Washington Weather Forecast Office 1/21/ PM EST

Next Scheduled Briefing 2200 UTC/ 5:00 PM EST Mon 21 Jan 2013 Thank you for your participation! 18NWS Baltimore/Washington Weather Forecast Office 1/21/ PM EST